Message 57098 - Python tracker

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Author	mark.dickinson
Recipients	alanmcintyre, inducer, loewis, mark.dickinson
Date	2007-11-04.15:16:21
SpamBayes Score	0.2349693
Marked as misclassified	No
Message-id	<1194189383.11.0.0300801460306.issue1381@psf.upfronthosting.co.za>
In-reply-to

Content
I took a look at this a while back, and got as far as writing a pure Python drop-in replacement for cmath, based on Kahan's "branch cuts for elementary functions" paper. This fixes a variety of problems in cmath, including the buggy branch cuts for asinh. File attached, in case it's of any use. As Tim Peters pointed out, the real problem here is a lack of decent unit tests for these functions. I have tests for the file above, but they assume IEEE754 floats, which is probably not an acceptable assumption in general.

I took a look at this a while back, and got as far as writing a pure 
Python drop-in replacement for cmath, based on Kahan's "branch cuts for 
elementary functions" paper.  This fixes a variety of problems in cmath, 
including the buggy branch cuts for asinh.  File attached, in case it's 
of any use.

As Tim Peters pointed out, the real problem here is a lack of decent 
unit tests for these functions.  I have tests for the file above, but 
they assume IEEE754 floats, which is probably not an acceptable 
assumption in general.

Files
File name	Uploaded
cmath_py.py	mark.dickinson, 2007-11-04.15:16:22

History
Date	User	Action	Args
2007-11-04 15:16:23	mark.dickinson	set	spambayes_score: 0.234969 -> 0.2349693 recipients: + mark.dickinson, loewis, alanmcintyre, inducer
2007-11-04 15:16:23	mark.dickinson	set	spambayes_score: 0.234969 -> 0.234969 messageid: <1194189383.11.0.0300801460306.issue1381@psf.upfronthosting.co.za>
2007-11-04 15:16:22	mark.dickinson	link	issue1381 messages
2007-11-04 15:16:22	mark.dickinson	create